Mineral separating apparatus



Feb, 10, 1942. J. B. couRENQ MINERAL SEPARATING APPARATUS Filed April 17, 1959 3 Sheets-Sheet l In ven Zar. Jean B. Euren? ar/zfy Feb.10,1942. B COURENQ I 2,272,365

' MINERAL SEPARATING APPARATUS Filed April 17, 1939 3 Sheets-Sheet 2 ean 3. arezz?.

Feb.- 10, 1942. 1 B COURENQ 2,272,365

MI NERAL S EPARAT ING APPARATUS Filed April 17, 1939 3 sheets-sheet 5 /ae /03 .50 f2' .5. fof 5j,

/z venan Jean B. Cba/'eng'.

Patented Feb. 10, 1942 UNTED T ES are

MINERAL SEPARATINGL APPARATUS.'

Jean B'. Courenq, Los-Angeles, Calif.

Application April-17, 1939, Serial No. 268,297

8 Claims.

This invention relates generally to mineral.

separators of the type commonly known as dry separators, and more particularly to that class of dry separator and separating process which operate. by mechanical agitation assisted byair currents.

Dry separators of the class referredto may be designedfor separation of flakes and nuggetsr of gold or platinum from gravel as found. in placer deposits, or for concentration of the valuableV usually inclined, andA is regularly shaken or re-Y ciprocated. The gold particles being heavy, tend. to sink through the mass ofmaterial, and are collected by pocketsy or rifes in the shaker orrile board. Air currents are often used' as anaid to separation, being frequently directed against and through screen members of which the bottom of the shaker or rilfle board is composed.

The general object of the present invention is to provide an improved dry separator of simple construction which has comparatively large capacity combined with a relatively high percentage of recovery of the values present.

The separator provided by the `present invention` embodies, in its preferred form, a shakermember mounted for vibratory movement along an inclined direction line, and having anl inclined surface or surfaces over which the incoming material is passed. The shaker is movedalternately slowly downwardly of the incline, and then quicklyback, being brought to a sudden stop on the up or back stroke. This novel action has the effect, on each up-or back stroke, of throwing the particles of gold, which are relatively heavy, back-wardly through the grovel, i. e., in a direction up the incline. To aid this action, the inclined surfaces of the shaker are formed with upwardly or rearwardly directed jagged formations or teeth. Because of their density, the gold particles sink' through the gravel and encounter these, teeth, which prevent them from sliding further downthev incline, but function to Ell throw: them up. the incline onzeach up stroke of 55 the shaker. Cooperating with this mechanical action are certain air currents, which act to separate the lighter material from the heavy,

tend to move the entire mass of gravel down` the incline, and orient thegold particles for most effective travelA back. through the lgravel and up theincline. The gold so induced to travel up the jagged or toothedinclined surface or surfaces is collected from time to time from the head end of saidl surfaces. The action of the separator is particularly effective and eicient, and recovery of as high as 95% of the contained gold is'commonly achieved.

The invention will be more fully understood from the following detaileddescription of apresent preferred embodiment thereof, reference for this purpose being had to the accompanying drawings, in which:

Fig. 1 is a longitudinal vertical section through aI machine in accordance with the invention;A

Fig. 2 is a section taken on line 2 2- of Fig. 1; Fig. 3 is an enlargement of` aportion of Fig. 1,

being a vertical longitudinal section through the shaker frame;

Fig. 4 is a section taken on line 4-4 of Fig. l; Fig. 5 is an end elevation` of theshaker frame, as viewed from the left in Fig. 3;

Fig. 6 is a View taken as indicatedl by arrows.

generally by the numeral i0, which supports` aninclined chute il. The latter comprises parallel inclined side members l2., and a bottom I3 abut-v ting against and secured to the lowerl edges of membersY l2. The side members I2 are securedto upright members I4 and l5 of frame l, inv

the manner indicated. Mounted on one of members I2, near its upper end,y and on a parallel member I2a that extends between frame member` Iliaand across-member |412, arebearings iifor a horizontal transversely extending drive shaft Il, said shaft carrying ar suitable fly-wheel i8, a cam I9, and a crank disk 20, here shown asintegral withcam I9. ShaftV l1 may be driven in any suitable manner, as for example by a handl crank; in the present instance, fly-wheel i8 is indicatedI as provided with a crank handle; 2l..

-crrioiEql by which the iiy-wheel and shaft may be rotated.

The gravel containing the mineral particles to be recovered, such as gold akes and nuggets, is deposited Within a hopper 25, which is mounted on supports 26 secured to and extending from the sides I2 of chute II. The hopper is preferably provided at the bottom with a gate 21 by means of which the rate of feed of gravel into the machine may be regulated. The bottom of hopper 25 is connected by means of flexible conduit or connection 28 with the upper end portion of a shaker frame generally designated at 3U, the latter being disposed Within chute I I, and means later to be described being provided for reciprocating it in a direction longitudinally of said chute.

Shaker frame comprises an upper end wall 3l, side walls 32, and lower end member 33. Members 3l and 32 are inwardly flanged at their lower edges, as indicated at 34 and 35, respec tively, and an angle member 36 extends between side 32 below the aforementioned member 33, having a iiange 31 in the plane of ilanges 34 and 35. tending longitudinally of chute II and secured in the angles formed between sides and bottom of the chute (see Fig. 4). langes 34 and 31 slidingly engage cross strips 4I and 42, respectively, which are secured to chute bottom I3. The described anges on the bottom of the shaker frame are adapted to slide on these members 40, 4I and 42 in a direction longitudinally of the chute. Air pressure is supplied to the shaker frame by way of the air space or chamber dened by strips 4U, 4| and 42 and the chute bottom. In order to hold the air pressurewithin this space 45, the upper sides of strips 45, 4| and 42 are faced with strips 46 of some suitable material such as leather, which will permit free sliding action of the shaker frame but will at the same time afford a sufficiently good seal against escape of air that the necessary pressure may be held.

To reduce sliding friction to a minimum, the shaker frame is preferably provided with some suitable anti-friction supports which will prevent the Vfull weight of the frame and contained material from becoming imposed on `the leather strips. As here typically shown, the shaker frame has at each end a pair of laterally projecting perforated supports 41, formed of hardened steel, which are slidable on short, hardened rails 48 mounted on chute sides I2 (see Figs. 6 and 9).

The shaker frame is provided a short distance below the upper edges of sides 32, with a top Wall 50 which extends from rear wall 3l to a point spaced somewhat toward the opposite end of the frame, being provided at that point with an inwardly turned flange portion 5I. A removable, flanged cover member 52 ts between said flange portion 5I and the aforementioned end member 33 of the frame, and extends the full distance between the sides 32 of the frame, as illustrated in Figs. 3 and`4. This cover member 52 is adapted to be secured in position as by means of screws 54 passing through its ilanges and the sides 32 of the shaker frame. The purpose of this cover 52 is to confine certain later described air currents that flow through the shaker frame, so that their velocity will be kept up and their action on the materials will be at a maximum.

The material. enters shaker frame 36 by way of a long slot 60 in top member 5t, falling Flanges 35 slidingly Vengage strips 40 exinitially upon a wall 6| which is parallel to top 50 and has its side edges abutting side walls 32. 'This member 5I has a flange 62 adjacent end wal1 3|, which may be secured to wall 3| by suitable means such as screws 63. Member 6I is parallel to top for a distance forwardly from end wall 3l, and then has a somewhat downwardly inclined portion 63a, terminating in a flange h turned at right angles to the top 50 of the frame. The material deposited on meA ber 6I by way of aperture 60 slides down incline 60a and over flange 60h.

Below member 6I, the shaker frame is provided with a series of jagged, slightly inclined step like surfaces 65, 66 and 61, which are arranged parallel to one another, and over which the material passes in succession. These surfaces or steps 65, 66 and 61 extend the full distance between side members 32, being secured at their edges to said members 32 in any suitable manner. The last step 61 is furnished with a flange 68 abutting angle member 36, and the material discharged from said step 61 passes out of the shaker frame by way of the outlet 69 between angle member 36 and the outwardly ilaring lower portion 68a of the previously mentioned end member 33.

In the present illustrative embodiment of the machine, chute II is disposed at an angle of approximately 30 with horizontal, so that shaker frame 30 is likewise disposed at an angle of sub stantially 30 with horizontal. Steps 65, 66 and 61 are arranged at such angle that 'when the shaker frame is in the machine they will have a downward inclination in the same direction, but at a much less angle; in a present illustrative embodiment, this angle is approximately 4 with horizontal. An angle substantially greater than 4 brings about too. great a tendency for the gold particles to travel downwardly by reason of gravity, While if the steps are too near horizontal, the benefit of gravity in moving the gravel down the incline is undesirably diminished. However, while I have specified 4 as being approximately correct for best results.

there is some available leeway on both sides of this angle within which eiiicient performance is obtained.

Attention is directed to the fact that the jagged steps 65, 66 and 61 are made up of a series of pointed teeth 10, somewhat in the nature of ratchet teeth, which are directed against the direction of gravel iiow through the shaker frame, or in other words, up the incline. These teeth, which areparallel and extend the full width of the steps between side members 32, act to catch the heavier particles of material (gold or other heavy values) that settle down Within the gravel passing thereover, holding said material against travel down the general incline, and tending to move that material in an upward direction when the shaker frame is moved upwardly of the chute. This action will be described in more detail at a later point in the specification.

As will be seen from an inspection of` Fig. 4, the upper end of rst step is just at or below the flange 65h on member 6I. Extending upwardly from the upper end of this step 65 is a wall member 1I, furnished at its upper end with an upstanding flange '12, the upper end of which is spaced a short distance below wall member 5I to provide a constricted air passage therebetween. Pressure air from the space 45 between the bottom of the shaker frame and chute bot tom I3, and which is developed as by a bellows system B, hereinafter to be more particularly described, passes. betweenv the upper end of this ange 1.2i and wall 6|', and. is` discharged into the space inside the shaker frame between the lower edge of flange 69hand. the wall member 1|n at theltop. of jagged'. stepv 65. Thisv air current has several functions, as will later be explained.

At the bottom of step 65- is a flange 1liY which is` turned downwardly, at right angle to step 65, the lower end of this flange being located just above the upper end portion of step- 66. A ange 12b" extending fromj the upper end of step 69, parallel to and spaced behindflange 15, affords an air passage from space 45 over the upper edge of flange 16, downwardly between said iianges, and outwardly below the lower edge of flange 15 across the teeth of step 66.. StepI 66 has at its lower end a down turned flange 18.

similar to thev flange 15- yof step- 65A. I preferably incorporate in the series of jagged or toothed steps a pocket adapted to catch or collect particles of gold of suchl large size that they might not be retained by the teeth 1-0, and in the present embodiment of the invention, such a pocket, indicated generally by numeral 89, intervenes between steps 66 and 61. Thus the material discharged from the lower end of step BS and falling over flange 18Y is caught by a somewhat downwardly inclined Wall 8|, which merges at the bottom into a channel or pocket 82. upper end of this wall 8| has a flange 83 spaced back of and disposed parallel to flange 18, thereby forming an air passage similar to that described at the head of the preceding step 66.

The wall member forming channel or pocket 82 has a section 82a extending downwardly from Said channel, approximately parallel to steps 65, 66 and 61, and terminates in a flange 84 similar and parallel to the flanges 15 and 18 at the lower edges of steps 65 and 66, the lower edge of this flange 84 being located above the upper end portion of the lowermost step 61. The upper edge of step 61 has an upturned flange 85 spaced back of and disposed parallelto flange 84, forming an air passage from space 45 between said flanges and discharging below the lower edge of'ange 84 in a direction downwardly of step 61.

The pressure air may be delivered into space 45 in any suitable or convenient manner. I here show a simple and convenient system for deliver- :i

ing a suitable supply of air by means of the simple bellows andv accumulator system designated generally at B. Preferably, a double bellows system is employed, the two members of which pump air alternately, so that a substantially continuous flow of air is developed. In the specic and preferred arrangement here shown, two bellows 86 and 81- are mounted on the underside of a horizontal supporting means 88, mounted in any suitable manner on legs I4 and l5, the two bellows being disposed in opposed relation, with their pivots 86a and 81a adjacent to one another, in the manner clearly illustrated in Fig. l. A connecting rod 99 is connected at its upper end to crank disk 29 and pivotally connected at its lower end to a bellows operating bar 9|, which is connected at 92 and at 93 with the movable sides of bellows 86 and 81, respectively. When connecting rod 99 is reciprocated by .crank disk 20, bellows operating bar 9| is caused to move in such a way as to work bellows 36 and 81 simultaneously but in opposed directions; thus, bellows 86 is closed as bellows 81 is opened', and vice. versa, so that the two. deliver air alternately.

Bellows 86 and 31 are diagrammatically indiair developed inside the shaker frame will notV cated as provided with usual intake valves at 86D ande 87H1,- respectively, and. with usual: discharge valves-86e and 81a, respectively, the latter both discharging into. a flexible tank or accumulator 95. These valves are of al conventional type and need not be detailed. Flexible tank or accumu-` lator 95 is made: up. of. typical bellows construction, having a. flexible, corrugad side Wall 95a, together with bottom 95h mounted on support 99.- and a topy 9.50 which. is. free to move in a vertical direction depending upon the pressure of thecontaned air. A flexible connection 9.9 connects flexible. tank 95 with the space 45 between chute` bottom |3 and the shaker member 39. Thus the upper end of this flexible connection 955, which may also. be of bellows construction, is fittedV around an aperture 91v in chute bottom t3. leading to space d'5. The lower end of flexible connection 95 is connected to the upper side 95h of flexible tank 95, communicated Withthe interior of tank 95. by way of a suitable opening Std/in member 95e.

For the purpose of distributing the air pressure uniformly within chamber or air space 45, a perforated deilector plate 99 is preferably mounted in said chamber over aperture 91 (Figs. 1 and 2), the air being delivered both through the perforations 99a in said deflector plate and 'also by Way of the openings 99. under the edges of said plate. Air deflector plate 98 is supported at a suitable elevation above trough bottom wall I3 by means of suitable feet or supports 98h located at its four corners,

A detachable connectionA is made between flexible tube 28 and the aperture 69 in the upper wall 5.9 of shaker frame 3l), and as here shown, this connection comprises simply an apertured block |09 mounted on the lower end of flexible tube 28 and engageable with wall 5E! around aperture Bil, this block having dovetail shaped edges 0| adapted to be received within a dovetail way provided by angular flanges |92 mounted on the upper wall 59 of the shaker frame. Connection is established between hopper 25 and the interior of shaker frame 39 by simply sliding this block |99 between flanges |92 until it engages a limiting stop |03, at which, time flexible tube 28v is in register with aperture 69. Preferably, the bottom surface of this block is faced with some suitable gasket material, as leather, so that the pressure escape at this connection.

Shaker frame 39 is alternately moved slowly forwardly (downwardly of the chute), and then quickly retracted, being brought to a sudden stop at the termination of its up or back stroke. This operation is accomplished by the aforementioned cam I9 on shaft I1, said cam I9 bearing against a roller |95 carried at one end of a follower or push rod |06, the latter being slidably mounted in a bearing |91 mounted on the aforementioned cross member Mb of the main frame. In order to maintain roller |95 in proper position with reference to cam I9, push rod H26 is furnished with a laterally projecting pin |99 which works in a longitudinal slot H9 in bearing |91. Push rod |96 projects from bearing |91 through an aperture in` cross member illb and its end acts against the upper `end of shaker frame 30. A coil compression spring H2 acting between a shoulder Ia on push rod |99 and a ring ||2a conned between bearing |91 and cross member Mib urges push rod |96 in a direction towards cam I9, acting to maintain follower roller |95 against said cam at all times.

The end of the shaker frame is provided in the center with an abutment I|4 adapted to engage against an anvil or stop member I I mounted on frame member |41); as a simple illustration of suitable means for this purpose, I illustrate a bolt mounted in frame member |41) and arranged with its head adapted to be struck by abutment |I4 (see Figs. 1 and 7 The abutment member II4 is mounted on the end of the shaker frame by means of a flange |I4a and screws 63. A reenforcing bar IIB is mounted immediately against the inner surface of end wall 3| opposite abutment H4, said member extending, preferably, the full width of the shaker frame. Having been advanced down the incline by cam I9 and push rod |06, the shaker frame is retracted by means of a pair of tension springs |20 connected between frame member |4a and a pair of eyes I2I secured to the end wall 3| .of frame 30, these springs |20 passing through apertures |22 in transverse frame member |4b. Another tension spring |24 is preferably connected between the rearward end of the shaker frame and the trough bottom, this latter spring serving to hold the shaker frame down during its vibratory movement.

Cam I9 is formed with a plurality of contiguous cam sections |30, here four in number. Each of these is of progressively increasing radius from the radial shoulder |3| of the preceding cam section to its own radial shoulder I3I. Follower roller |05 rides these cam surfaces |30, and under the iniluence of push rod spring ||2, moves inwardly or towards the axis of the cam as it passes over shoulder I3 I Thus it will be evident that during a quarter revolution of the cam, follower roller |05 and push rod |05 are slowly advanced, and then, as roller |05 passes over cam shoulder |3I, the roller and the push rod are quickly retracted by spring II2.

In the course of the described advancing movement of push rod |00, its end nally engages the endy of shaker frame 30, and moves the latter, against springs |20, in a direction down the ineline of chute I3, The relations are preferably such that frame 30 is moved, typically, approximately 1/8" by this action of push rod |06; however, while this figure is given as typical and preferable, it is to be understood that no limitation is intended. At the moment that follower roller |05 then passes over cam shoulder |3I, the push rod is quickly retracted by spring I|2, leaving shaker frame 30 to be retracted by springs |20 The latter then pull the shaker frame in an upward direction until abutment |I4 strikes against anvil or stop member I5. Springs |20 are suiciently strong that the shaker frame. is retracted very quickly and suddenly, and there is accordingly a substantial impact as the frame strikes stop member |I5. As will become apparent hereinafter, the sudden stopping of the frame brought about by bringing it sharply against stop member ||5 induces a novel type of separating action.

The operation of the machine is as follows: the material to be separated, as placer gravel containing gold, platinum or other heavy values, is deposited within hopper 25, gate 21 being regulated so that the material flows at a proper rate by way of flexible connection 28 to the interior of shaker frame 30. The material strikes rst against wall member 6|, and flows from there over steps 65, 65 and 61 in succession, finally being discharged from lthe shaker frame by way of the discharge opening at the foot of step 61.

The material so discharged is caught by chute I3 and conveyed by the latter out of the machine. Rotation of shaft Il by means of crank 2| operates bellows 86 and 0l to develop air pressure within flexible tank 95. The pressure air flows from by way of connection 96 to the chamber 45 below shaker frame 30, being distributed by deflector plate 98 to flow more or less uniformly into the several entrance openings in the bottom of the shaker frame. By reason of the dual bellows system pumping into the iiexible accumulator for tank 95, the delivery of air into chamber 45 is quite uniform. The pulsations which would occur if it were not for accumulator 95 are smoothed out and a substantially continuous flow of air delivered. This air flows by way of the previously described air passages in shaker frame 30 to be discharged at the head end of the several jagged steps, being discharged across the latter in the general direction of the iiow of material thereover. 'I'he discharge of air at th'e head end of each of the steps acts on the material falling onto the corresponding step member to separate out and blow in a forward direction the lighter constituents of the material, and also acts to move the mass of material down the incline. The air discharged below flange 18, at the head end of the section 3| designed for collection of comparatively large particles of gold, of course functions in a similar manner, 'I'he air so injected within frame 30 is finally discharged at the lower end of the frame, along with the discharged material.

The mechanical vibratory action of the shaker frame has been previously described; it Will be recalled that this action consists of a relatively slow movement down the incline, followed by a quick retractive movement, the latter being sharply terminated by engagement of the frame against an impact member. As previously mentioned, the vamplitude of this vibratory action is typically approximately 1/8. Assuming shaft Il to be rotated at a rate of two revolutions per second or a little less, frame 30 will be driven against stop member I I5 at a rate of seven or eight times per second. At such a speed, the machine is very efficient and effective in action. The particles of gold are of course considerably heavier than the gravel or material from which they are to be separated. They therefore, as frame 30 is agitated, settle quickly through th'e gravel until they engage teeth 10 on step members 65, 66 and 6l. These teeth 10, being directed up the incline, hold the particles of gold from sliding down the inoline. If the incline were too great, or th'e downward movement of the shaker should be too rapid, the gold particles would nevertheless, to some extent at least, travel downwardly along these jagged steps. vBy having the incline of steps 65 not too steep, as for example approximately 4, and by moving the shaker frame relatively slowly during its downward travel, I am able to prevent practically all of the gold particles which have come into engagement with teeth 'I0 from travelling down the incline.

On the up stroke of shaker frame 30, the gold particles which have come into 'engagement with teeth 'I0 are thrown by said teeth in a. direction op the incline. These particles, having become caught by the teeth, are carried along by the latter on the up-stroke of the shaker frame, and when the frame comes to its sudden stop by impacting against stop member I I5, the particles of gold which have been carried upwardly by these teeth are projected forcibly in an upward direction, :that is,fupwardly;of1the incline. These particles lforce their way vthrough the zgravel, and

" nally come to rest lat'theh'ead endof Athe :par-

ticular jagged surface or ystep .which "separated them oatfromthegravel. Apeculiaractionof the air currents on these .gold .particles is to be noted. Placer gold is usually principally vin the :form fof more or less fiat particles or flakes of various sizes and irregular outlines. The .air currents flowing parallel to the jagged steps within the shaker frame, particularly when the .cover .is in place, are suiciently strong as to orient these attish particles of gold parallel .to-the direction of airflow, and also to cause .them to stand on edge, the action being vsomewhat analogous vto the action of wind on the tai-l fof a windmill. This places the gold particles in positions most advantageous for their travel backwardly through the gravel. A number lof gold particles pare indicated in Fig. 8 as having accumulated at th'e head end of step 66. 'These particles will vrremain in this position until removed from Athe shaker frame.

Of course, some of the gold yparticles will not come into engagement with the jagged surface of the first step 65, and will be carried over onto secondv step 66. And similarly, some of ithe gold particles may not be caught by second step 66, and will pass on down over section 8| and onto last step 61. 66 and 61 is, however, adequate to remove a very high percentage of the contained gold, unless-the material is flowed through the machine at an undue rate of speed. Any particles of ygold too large to be caught and moved by 'teeth 1U work f down in the gravel within section 8| 'and are caught by pocket 80.

The rate at which the material is run through the machine must of course not lbe too great, be-

cause of the likelihood of carrying out some of the gold. On the otherhand, the separating action of the machine is so definite and positive that the material may be handled at good speed. The proper or most efficient speed for any given material may easily be ascertained Yby experiment. As previously explained, the upwardly directed teeth on the stepped surfaces aid in preventing the particles of gold from going down the incline, and also aid in vthrowing those vparticles up the incline on the back stroke of the shaker frame. Of course, even without the teeth, the gold particles would to some extent be moved up the inclined steps, simply by virtue of the characteristic movement given to the shaker frame. teeth, however, the separating action becomes positive and rapid. The functional part fulfilled by the air currents must not be minimized. These air currents, discharged at the head end of the jagged steps, act, first, to blow forwardly the lighter constituents of the material, second, to move the mass of gravel down the steps in succession, and third, turn the flakes of gold parallel to the air currents and on edge, so that they may work themselves most readily through l.

the gravel. The incline of the jagged steps is of importance. 'I'hese steps must not be too steep, as otherwise the particles of gold are carried out. An incline of about 4 affords optimum results, though the machine will operate e successfully with the surfaces horizontal. The direction line of reciprocative movement of the shaker frame is not critical, though it is convenient and preferable to move it parallel to the dis.- charge chute. The essential in this respect 1s The succession of three steps 65,

Once in engagement with the simply that `.the :shakerihave a .component Vof 'movement ion :the back 'stroke fsuchthatwhen it Ais suddenly stopped, the vgold particles'will `be thrown in directions :up the 'jagged 'inclined `surfaces or :steps The speed of movement of the shaker .frame Ais governed by two considerations;

first, 'the .speed on the vdown or forward stroke must not 'be so ,great as to cause the goldparticles tto :move down the .inclined surfaces when that stroke .is stopped, :and second, -thespieed on the vup or lback fstroke must -.be sufcient that, when the :movement of the frame is'suddenly arrested, Vthe gold particles will `be thrown backward'ly through the gravel. In summary, the

vessential of the required reciprocative movement risthat it includes the application ofla sudden accelerative 'force (here specifically the :sudden stopping force) to the shaker frame in a direction opposite vto the direction in which the impelling'surfaces ofthe teeth face.

I claim:

l. A 'separatorcomprising la shaker frame having a series of step-like surfaces at successively lower elevations over which material to be separated may be passed in succession, each of said surfacesbeing slightly downwardly inclined, and the pitch of the series of steps formed by said surfaces being substantially greater than the inclination of individual surfaces, teeth on said surfaces directed oppositely to the direction of said downward inclination, means supporting said shaker frame 'for longitudinal reciprocative movement, and means -connected with said shaker frame for imparting to ita succession of quick, abruptly arrested movements in the direction in which said teeth are directed.

v2. A separator comprising a reciprocative shaker frame, a slightly inclined surface on said frame, van apron depending from the lowermost edge of said surface, a second surface fon said frame .disposed substantially parallel to and at la lower elevation than said first mentioned surface, the uppermost edge of said second surface being overhung by said apron Von said first mentioned surface, and 4the major portion of said second surface 'projecting forwardly `beyond said apron, teeth on said surfaces `directed upwardly of the incline of said surfaces, and an upstanding flange at the uppermost edge of said second mentioned surface, said flange and said apron cooperating to define an air discharge passageway opening at the upper end of said second surface.

3. A separator comprising a shaker frame embodying a nearly horizontal surface having a head end and a foot end, said surface having impelling teeth extending thereacross and directed toward the head end thereof, means supporting said shaker frame for reciprocative movement in a general direction longitudinally of said toothed surface, means for depositing material to be separated onto the head end of said surface, means for discharging air under pressure along a line extending across the head end of said surface, said means directing the air along said surface from the head end toward the foot end thereof, and means for imparting to said shaker frame a succession of quick, abruptly arrested movements in the direction in which said teeth are directed, alternating with relatively slow movements in the reverse direction.

4. A separator comprising a shaker frame embodying a surface having a head end and a foot end and having a slight downward incline from its head end to its foot end, said surface having impelling teeth extending thereacross and di- 'rected toward the head end thereof, means supporting said shaker frame for reciprocative movement in a general direction longitudinally of said toothed surface, means for depositing material to be separated onto the head end of said surface, means for discharging air under pressure along a line extending across the head end of said surface, said means directing the air along said surface from the head end toward the foot end thereof, and means for imparting to said shaker frame a succession of quick, abruptly arrested movements in the direction in which said teeth are directed, alternating with relatively slow movements in the reverse direction.

5. A separator comprising a shaker frame embodying a nearly horizontal surface having a head end and a foot end, said surface having impelling teeth extending thereacross and directed toward the head end thereof, means supporting said shaker frame for reciprocative movement in a general direction longitudinally of said toothed surface, means for discharging material to be separated from an elevation spaced above and along a line extending across the head end of said surface so as to fall onto the head end of said surface, means for discharging air under pressure along a line extending across the head end of said surface and just above said surface and just back of the material falling onto said surface, said means directing the air from the head end toward the foot end of said surface, so as to act on the material as it falls onto said surface to blow the lighter constituents thereof toward the foot end of said surface, and to move the mass of material on said surface toward the foot end thereof, and means for reciprocating the shaker frame in a direction generally longitudinal of the toothed surface and for periodically applying to the. shaker frame a sudden accelerative force in a direction opposite to the direction of the teeth.

6. A separator comprising a shaker frame embodying a surface having a head end and a foot end and having a slight downward incline from its head end to its foot end, said surface having impelling teeth extending thereacross and directed toward the head end thereof, means supporting said shaker frame for reciprocative movement in a general direction longitudinally of said toothed surface, means for discharging material to be separated from an elevation spaced above and along a line extending across the head end of said surface so as to fall onto the head end of said surface, means for discharging air under pressure along a line extending across the head end of said surface and just above said surface and just back of the material falling onto said surface, said means directing the air from the head end toward the foot end of said surface, so as to act on thematerial as it falls onto said surface to blow the lighter constituents thereof toward the foot of said surface, and to move the mass of material on said surface toward the foot end thereof, and means for imparting to said shaker frame a succession of quick, abruptly arrested movements in the direction in which said teeth are directed, alternating with relatively slow movements in the reverse direction.

7. A separator embodying a reciprocative shaker frame having a series of comparatively short, toothed surfaces arranged cn said frame at successively lower elevations in step-like formation, and over which material may iiow in succession, the teeth of said surfaces extending transversely thereacross and being directed upwardly of the series of steps formed by said surfaces, air passageways adapted to discharge air under pressure in a direction against said teeth from a position immediately above the ends of said surfaces towards which said teeth are directed, and means for imparting to said shaker frame a succession of quick, abruptly arrested movements in the direction in which said teeth are directed.

8. A separator comprising a reciprocative shaker frame, an inclined surface on said frame along which material may flow, an apron depending from the lowermost edge of said surface, in front of which material flowing off the lower end of said inclined surface may fall, a toothed sur face on said frame at a lower elevation than said first mentioned surface and arranged with one end portion positioned below and overhung by said depending apron, and with its major area projecting forwardly beyond said apron, the teeth of said surface extending transversely thereacross and pointing in the direction of said apron, the lower edge of said apron and the upper end portion of said toothed surface cooperating to define an air discharge passageway opening across said toothed surface, and means for imparting to said shaker frame a succession of quick, abruptly arrested movements in the di rection in which said teeth are directed.

JEAN B. COURENQ. 

